Admit it. When you’re not up to snuff the little things you normally let roll off your back annoy the daylights out of you.

Am I correct? Of course I am.

Allow me, then, this brief rant about how this kind of off-kilter feeling can get in the way of relationships.

I went to work Saturday but didn’t bring my “A game” to the job, which is to greet people courteously at the auto dealership where I spend about 25 hours each week. I did fine with the customers who came through.

My colleagues ticked me off. Repeatedly. They didn’t know it, although I did tell one of them about my sour mood. She understood, having been through them herself from time to time.

I cannot diagnose the cause of my crabbiness. It might been simply being unable to spend more time with our precious granddaughter who came with her parents to see us on a fairly impromptu visit over the Fourth of July weekend.

Then came this moment of pique that on a good day wouldn’t have bothered me in the least. Maybe there’s a cautionary tale here.

One of the sales staffers walked past me and said, “How’s it goin’?” I turned around quickly, but only saw him slip through the door and into the hallway.

What? Why didn’t he wait to hear my answer? Why, I never …

I vented my frustration at that moment to another colleague, who then looked at me as though I’d just grown another head. He didn’t get it. More likely he didn’t care.

Now that I’ve cooled off, I get that he didn’t care. On a better day I wouldn’t have cared much either.

I thought a few moments later about something my congressman, Mac Thornberry, once told me. He said he instructs his young staffers to exercise good manners when dealing with the public. Say “you’re welcome” when someone thanks you, he said, adding that he dislikes people who say “no problem” in response to a simple “thank you.” I agree with that.

He might add this instruction to his staff: When you ask someone “How’s it goin’? or “How you doin’?” stick around long enough to hear the answer.

There. Rant over.